The present invention relates to radar signal processing. More particularly, the present invention relates to the post-matched filter processing repair of radar return signals.
Range sidelobe suppression in radar pulse compression has been a topic of intense scrutiny for several years. The goal is to minimize the effects caused by the correlation of a transmitted waveform with delayed versions of itself while maintaining close to the optimal signal-to-noise ratio (SNR). One approach has sought to achieve this by employing some form of least squares (LS) estimation; see, for example, U.S. Pat. No. 5,805,107. LS has been shown to provide the most efficient estimator when the additive noise is white. However, LS is not robust in that it does not account for scatterers closer than some nominal range R0, which can have a deleterious effect on the estimation of the channel at the ranges of interest.
Another approach termed Reiterative Minimum Mean-Square Error (RMMSE) estimation and described in U.S. Pat. No. 6,940,450, issued Sep. 6, 2005 and incorporated herein by reference, provides a robust estimate of the radar channel impulse response that is almost completely devoid of range sidelobes. This approach, however, as with LS estimation, involves replacing the standard matched filter within legacy radar systems, which is not always a feasible solution.
It would therefore be desirable to provide an approach for decreasing the radar sidelobes after a,standard matched filter radar signal processing operation.